硅纳米孔柱阵列及其铜复合纳米体系的制备与表征

【作者】 杨晓辉；

【导师】 李新建；

【作者基本信息】 郑州大学 ， 凝聚态物理， 2004， 硕士

【摘要】 铜／硅纳米孔柱阵列复合纳米薄膜具有重要的潜在应用价值，而精确控制纳米粒子的大小、结构和分布则是应用的关键。本文通过水热法制备了具有明显尺度结构层次的硅纳米孔柱阵列(Si-NPA)，并采用浸渍镀膜方法制备了铜／硅纳米孔柱阵列复合纳米薄膜(Cu／Si-NPA)。系统研究了Si-NPA的形成机理、微观形貌特征及Cu／Si-NPA的形貌特征与薄膜样品制备过程中的反应时间、样品制备后退火温度等条件之间的关系和规律。具体研究结果如下： 第一部分：Si-NPA 1．通过对Si-NPA形成机理的研究，发现在Si-NPA制备过程中存在两种腐蚀机制：对缺陷位的化学腐蚀和通过形成大量微电解池进行的电化学腐蚀。Si-NPA的形成主要是取决于电化学腐蚀过程。 2．新鲜制备的Si-NPA具备下述结构特点：(1)Si-NPA是具有明显的尺度结构层次的微米／纳米结构复合体系；(2)在微米层次上，Si-NPA由大范围均匀排列的、彼此很好分离的硅柱组成，柱的横截面尺寸约为1.5nm；(3)在纳米层次上，Si-NPA中的硅柱均呈多孔状，孔径在～20-40nm，孔壁由粒径约为5nm的硅纳米晶粒组成。 3．对Si-NPA在氮气氛围内进行退火后，样品在微米层次上基本保持退火前样品表面的规则阵列排布形式；在纳米层次上，退火后样品表面的硅柱仍呈多孔状，但孔壁的硅晶粒由退火前的5nm长大为退火后的17.2nm。 第二部分：Cu／Si-NPA 1．在复合薄膜的制备过程中，薄膜保持了硅纳米孔柱阵列的排布形式，反应时间超过7小时后，规则阵列排布的特征消失。 2．在溶液浓度保持不变的情况下，随着反应时间的的延长，铜的沉积量逐渐增加，铜纳米颗粒的平均晶粒尺寸逐渐长大。 郑州大学硕士学位论文硅纳米孔柱阵列及其铜复合纳米体系的制备与表征当反应时间超过30分钟后，铜纳米颗粒明显地呈现出两种不同的尺寸分布，聚集于硅柱顶端的铜纳米颗粒的平均尺寸明显大于沉积于硅柱侧面以及硅柱之间的铜纳米颗粒平均尺寸。前者主要是由初始晶核的长大、团聚而成，后者则主要由二次成核生长而成。在退火过程中，铜纳米颗粒发生了两个变化:一是铜纳米颗粒向硅柱的运动;二是铜纳米颗粒间的合并。在退火时间保持不变的情况下，随着退火温度的升高，铜纳米颗粒的平均晶粒尺寸逐渐长大。更多还原

【Abstract】 The Cu/silicon nanoporous pillar array(Cu/Si-NPA) composite nano-systems is valuable in industrial applications, and the precise control of the morphology, the grain size as well as its distribution are key factors, In this thesis, Silicon nanoporous pillar array(Si-NPA) were prepared by hydrothermally etching single crystal silicon wafers in the solution of hydrofluoric acid containing ferric nitrate and Cu/Si-NPA were prepared by electroless plating. The formation mechanism and the morphology of Si-NPA were studied systematically. The dependence of the morphology, the grains size and the component of Cu/Si-NPA on the immersion time and annealing condition were investigated. Main points are concluded as follows:PARTI: Si-NPA.1. The morphologies observed at different etching stages shows that there are two co-exists etching mechanisms in the formation process of Si-NPA: the chemical etching of defects and the electrolytic etching through forming local micro-electrolyzers. The etching process was initially dominated by the chemical etching and then electrolytic etching. The latter played a key role to the formation of the final Si-NPA.2. Si-NPA is composed of large quantities of well-separated, quasi-identical siliconpillars with a cross section size of ~1.5 m. These silicon pillars are uniformlyarrayed and perpendicular to the surface. The pillar is nanoporous and its frame is composed of silicon nanocrystallites sized ~5nm.3. After being annealed in nitrogen, the structural feratures of Si-NPA, such as pillar array, porousity et al, are maintained, but the silicon grain size increased from 5 nm to 17.2nm.PART II: Cu/Si-NPA1. During the immersion process, Cu/Si-NPA inherits the morphology of Si-NPA. But after seven hours or longer immersion, the morphology characteristics of the Si-NPA disappear.2. Both the amount and the grain size of the copper nanocrystallites increase with immersion time under the same solution concentration.3. For Cu/Si-NPA immersed over 30min, there appeared two size-distributions of the copper nanocrystallites. The particles assembled at the top of silicon pillars is larger than those assembled at other places. The former mainly originates from the aggregation among the particles growed from initial nucleation, while the latter mainly comes from the ones from second nuleation.4. During annealing process, two steps occured: one is the propergation of the copper nanograins towards silicon pillars; and the other is the coalescent of the adjacent nanoparticles. Keeping the annealing time unchanged, the size of the copper nanograin increases with annealing temperature.更多还原